Players can opt to hold out from a team for any number of reason. Previously the team could sit on the player and deal with him at their leisure. Hold Outs have been changed to have a much more significant impact on your team.
ON THE ICE
If you opt to put a Hold Out Player on your Game Roster, they now have a 25% chance / skill to impose a -2 modifier to any player's skill that are on the ice with them (including the goaltender). If you have multiple Hold Out Players, the chance stacks (3 Hold Outs will impose a 75% chance to impose a -2 if they are all on the ice together). The lowest that a player's skill can drop to is still 1.
For leagues that use Age Rerates (by default), each Hold Out Player imposes a -50% chance to the Increase % to their own rerates and also impose a -25% chance to the Increase % for ALL PLAYERS ON THEIR TEAM. Any extra % remaining from the penalty will be added to the Decrease %. The effect is cumulative so having 3 Hold Out Players will impose a -75% Increase % penalty to all non-Hold Out Players.
CLEARING THE HOLD OUT FLAG
In most cases, a Hold Out Player will just not negotiate with that team and can be dealt to another team. In most cases, when you trade a Hold Out Player to another team, the Hold Out flag drops off and the player will be back to normal with their new team.
In the case of players holding out for Free Agency, this is different. The Hold Out flag is ONLY removed once Free Agency starts and the player has been removed from their team (Free Agency started and their Contract was at 0 years). In cases where the player is still under contract for 1 or more years the only option to remove the player is to buy them out. Trading a player that is holding out for Free Agency will not clear their Hold Out flag.
In cases where the Auto-GM gets a Hold Out Player they will attempt to send out low-ball offers to all other applicable teams in order to move the player off their roster.